Ceramic Honeycomb Filter Production Using Planetary Blending
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Solution Overview
Problem
Existing methods for producing ceramic honeycomb filters face challenges in achieving high porosity without defects such as cracks and undulations due to microcapsule breakage from excessive shearing forces and air entrapment during blending, leading to low particulate-matter-capturing efficiency and pressure loss.
Innovation Solution
The method involves using a pressure kneader to blend ceramic materials with microcapsules under controlled pressure (0.12-0.5 MPa) and vacuum conditions to minimize shearing forces and air introduction, followed by piston-type extrusion molding to prevent microcapsule breakage and ensure uniform blending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a screw-type vacuum-blending machine is used to uniformly blend moldable material and remove air, then blending uniformity and air removal are improved, but microcapsules are broken by excessive shearing force, resulting in reduced porosity
Solution Approach 1:
The patent replaces the screw-type mechanical blending system with a planetary blending machine that uses a different mechanical mechanism (planetary motion with multiple blades) to achieve uniform blending with lower shearing forces, thereby preserving microcapsule integrity while maintaining blending effectiveness
Solution Approach 2:
The patent changes the blending parameters by using a planetary blending machine with controlled rotation speeds and blending times, creating a blending environment that achieves uniformity without excessive shearing forces that would break microcapsules
2Manufacturing precision
If microcapsules are used as pore-forming material to obtain higher porosity, then porosity is improved, but microcapsules are easily broken by shearing force, resulting in reduced porosity and poor shape retention
Solution Approach 1:
The patent replaces high-shearing screw-type blending with planetary blending that generates lower shearing forces, allowing microcapsules to maintain their structural integrity while still achieving uniform distribution in the moldable material
Solution Approach 2:
The patent uses microcapsules with specifically designed shell thickness (0.1-2 μm) that provides sufficient strength to resist breaking during blending while maintaining the desired porosity when intact
3Manufacturing precision
If a large amount of microcapsules are added to obtain desired porosity, then porosity is improved, but moldable material viscosity decreases, resulting in poor shape retention and dimensional accuracy
Solution Approach 1:
The patent optimizes the amount of microcapsules added and adjusts the molding pressure parameters to compensate for the viscosity reduction, maintaining both high porosity and good dimensional accuracy through controlled processing conditions
4Manufacturing precision
If low-speed blending is used to reduce microcapsule breakage, then porosity is improved, but blending uniformity is insufficient, resulting in non-uniform moldable material with defects
Solution Approach 1:
The patent uses a planetary blending machine with multiple blades rotating in different directions and speeds, creating a blending mechanism that achieves uniform mixing at lower overall speeds, preventing microcapsule breakage while ensuring composition uniformity
Solution Approach 2:
The planetary blending machine uses multiple blending blades segmented into different zones with different rotation characteristics, creating localized blending zones that collectively achieve uniform mixing without requiring high overall blending speed
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in honeycomb structures with porosity ranging from 50-70%, suitable for large diameters, and reduces defects like breakage and undulation, enhancing particulate matter capture efficiency and reducing pressure loss.
Implementation Method 1
blend under controlled pressure (0.12-0.5 MPa) and vacuum conditions to minimize shearing forces and air introduction
Implementation Method 2
microcapsules (gas-containing resin balloons) described, for instance, in JP 2003-38919 A have recently got used as a pore-forming material
Data Source
Figure 1(a)~1(b)
Figure 2~3
AI summary
A method for producing a ceramic honeycomb filter by blending a starting material mixture comprising a ceramic material, a molding aid and a pore-forming material under a pressure of 0.12-0.5 MPa in a pressure kneader to form a moldable material for a honeycomb extrudate.